vi Commands

vi is a Visual Editor (hence the name -- vi for VIsual). vi is a widely-used and popular UNIX-based text editor. Like most UNIX system interfaces and other text editors, it lets you control the system by using the keyboard rather than a combination of mouse selections and keystrokes.

Edit a File

Edit a file from command prompt	vi
Edit a file from command prompt for reading only	vi -R
Edit a file from within vi	:e
Edit a new file from within vi, discard changes to current file	:e!
Reload current file, discarding changes	:e!
Go forwards a page	Ctrl+F (or PgDn)
Go backwards a page	Ctrl+B (or PgUp)
Move around single lines or characters	Arrow keys
Save changes	:w
Save changes and override protected (read-only) files	:w!
Save changes and exit vi	ZZ
Quit	:q
Quit and discard changes	:q!
Get general help	:help
Get help on a command (eg. :set)	:help set

Go to lines, find matching text 

Go to line 1234 (do not see typing)	1234G
Go to line 1234 (see typing)	:1234
Go to start of file	1G
Go to end of file	G
Find (forwards) a line containing "swordfish"	/swordfish
Find (forwards) a line using a regular expression	/you see .* here
Repeat last search	n
Repeat last search in opposite direction	N
Find (backwards) a line containing "swordfish"	?swordfish
Find (backwards) a line using a regular expression	?you see .* here
Search case insensitive (Ignore Case)	:set ic
Search with case sensitivity	:set noic
Wrap searches back to start of file	:set wrapscan
Do not wrap searches	:set nowrapscan

Insert Text

Insert after cursor	i
Insert before cursor	a
Insert at beginning of line	I
Insert at end of line (append)	A
Open (start) new line below cursor	o
Open (start) new line above cursor	O

Advance Deletion

Delete next 5 lines	5dd
Delete to end of line	d$
Delete to start of line	d0
Delete to word "swordfish"	d/swordfish
Delete to the letter "x"	dfx
Delete lines 10 to 20	:10,20d
Delete current line and another 5 lines	:.,+5d
Delete all lines	:%d
Delete current word	dw
Find line containing pattern, delete it	:/pattern/d
Find line containing "dog", delete until line containing "cat"	:/dog/,/cat/d
Delete from current line to line containing "foo"	:.,/foo/d

Reset Joomla administrator password?

Joomla's admin username can be easily changed with a simple MySQL query.  Open mysql console and execute the following query


UPDATE `jos_users` SET `password` = MD5( 'new_password' ) WHERE `jos_users`.`username` = "admin"

Windows Shortcut Keys

Below is a listing of all the major Windows shortcut keys

Shortcut Keys	Description
Alt + Tab	Switch between open applications.
Alt + Shift + Tab	Switch backwards between open applications.
Alt + double-click	Display the properties of the object you double-click on. For example, doing this on a file would display its properties.
Ctrl + Tab	Switches between program groups or document windows in applications that support this feature.
Ctrl + Shift + Tab	Same as above but backwards.
Alt + Print Screen	Create a screen shot only for the program you are currently in.
Ctrl + Print Screen	Creates a screen shot of the entire screen
Ctrl + Alt + Del	Reboot the computer and brings up the Windows task manager.
Ctrl + Shift + Esc	Immediately bring up the Windows task manager.
Ctrl + Esc	Bring up the Windows Start menu. In Windows 3.x this would bring up the Task Manager.
Alt + Esc	Switch Between open applications on taskbar.
F1	Activates help for current open application.
F2	Renames selected Icon.
F3	Starts find from desktop.
F4	Opens the drive selection when browsing.
F5	Refresh Contents to where you were on the page.
Ctrl + F5	Refreshes page to the beginning of the page.
F10	Activates menu bar.
Shift + F10	Simulates right-click on selected item.
F4	Select a different location to browse in the Windows Explorer toolbar.
Alt + F4	Closes Current open program.
Ctrl + F4	Closes Window in Program.
F6	Move cursor to different Windows Explorer pane.
Alt + Space bar	Drops down the window control menu.
Ctrl + (the '+' key on the keypad)	Automatically adjust the widths of all the columns in Windows explorer
Alt + Enter	Opens properties window of selected icon or program.
Alt + Space bar	Open the control menu for the current window open.
Shift + Del	Delete programs/files without throwing them into the recycle bin.
Holding Shift	Boot Safe Mode or by pass system files as the computer is booting.
Holding Shift	When putting in an audio CD, will prevent CD Player from playing.
Enter	Activates the highlighted program.
Alt + Down arrow	Display all available options on drop down menu.
* (on the keypad)	Expands all folders on the currently selected folder or drive in Windows Explorer.
+ (on the keypad)	Expands only the currently selected folder in Windows Explorer.
- (on the keypad)	Collapses the currently selected folder in Windows Explorer.

Ubuntu Linux: How do I install .deb packages?

dpkg is a tool to install, build, remove and manage packages. dpkg itself is controlled entirely via command line parameters. For example -i use to install .deb file.

How do I install .deb file?

To install package called package.deb type the following command:
Go to directory where package.deb is kept. For example if it is in /tmp directory:

$ cd /tmp

Type the following command:

$ sudo dpkg -i package.deb

VI Editor Tips

The VI editor is a screen-based editor used by Linux/Unix users. The VI editor has powerful features to aid programmers.  VI has two modes insertion mode and command mode.  The editor begins in command mode. Insertion mode begins upon entering an insertion or pressing 'i' in keyboard. [ESC] returns the editor to command mode.

Following tips may be helpful for programmers / content writers.
Execute the command from VI Editor command mode. (press Esc, If Insert mode)


Insert space/character between 2 adjacent characters

Example 1
'LinuxFor' becomes 'Linux For' (Sentence Case)

:%s/\([a-z]\)\([A-Z]\)/\1 \2/g

Example 2
'Kerala government' becomes 'Kerala Governemnt'

:%s/\([a-z]\) \([A-Z]\)/\1 \U\2/g


Removes all lines starts with a word/patterrn.

Removes all lines begin with 'Ele'

:g/^Ele.*$/d

Removes all lines end with 'are'

:g/$*.are/d

Removes blank lines

:g/^$/d

Make First Letter Capital

:%s/^./\U&/



Find out a file which contains specific string

To find out a file which contains specific string, execute the following command from shell

# find /var/www/html/mysite-iname '*php' | xargs grep 'about' -s1

Here, searchesfor file which contains string 'about' .

Compress and split large files under linux

One of the common problems we used to face is transferring large files from Linux through mediums that doesn't support large files, especially when it comes to more than 4 GB files, usually that is a virtual machine hard disk, or backup file.

To compress and split files under linux, this command can be used:


$ tar -cvj big-file.dvi | split -b 650M -d - "small-file.tar.bz."

This command will compress and split the "big-file.dvi" to many files with size 650MB for each, giving it the name "small-file.tar.bz.0, small-files.tar.bz.1, etc...."

To join the files together again, this command can be used:

$ cat small-file.tar.bz.* > big-file.tar.bz

and to extract the output file :

$ tar -xvj large-file.tar.bz